This invention relates to a kitchen cooking oven and, in particular, an oven having an infrared gas broiler with a venturi tube for supplying the fuel gas and drawing atmospheric combustion air through the venturi tube.
Conventional kitchen ovens, domestic or commercial, that are used for cooking food often have plural modes of operation, including broiling, baking, warming, self-cleaning and the like, and such ovens commonly use either gas or electricity but not both until recently. Electric ovens have certain well known advantages over gas ovens, such as being substantially completely sealed to retain all of the heat for efficiency, whereas gas ovens must have fresh air inlets for both primary combustion air and secondary air, as well as a vent for discharging the combusted gases. Conversely, gas ovens have certain well known advantages over electric ovens, such as more even heat for broiling. In particular, infrared gas broilers provide extremely uniform and high temperature broiling heat that is not possible with electric heating element broilers that normally have a limited number of heating element rods spaced a significant distance apart that produce uneven heating.
However, the desirable high heat produced by an infrared gas broiler system located in the ceiling of an oven also creates certain potential problems that may occur under unusual circumstances or use of the oven. One such potential problem is a so-called xe2x80x9cflame roll-outxe2x80x9d after opening, closing and reopening the oven door within a very short time frame whereupon a portion of the layer of burning gas escapes through the top portion of the open door as insufficiently combusted gas. Another such potential problem is a so-called xe2x80x9cflash-backxe2x80x9d of the flame in the venturi tube (that supplies the fuel gas and draws atmospheric combustion air into the tube) when the tube becomes very hot and insufficient air is being drawn in for complete combustion. These potential problems are less likely to occur in an all-gas oven because of the conventional secondary air inlets at the bottom of the oven but to add such inlets to an electric oven to accommodate the infrared gas broiler would reduce the efficiency of the electric operation of the oven.
Accordingly, it is a principle object of the present invention to provide a positive air flow apparatus to an infrared gas broiler in an oven to stabilize and improve the operation of the infrared gas broiler. A further object of this invention is to provide such a positive air flow apparatus in which ducting is mounted on a back wall of the oven and extends over the air supply opening of the venturi tube of the infrared gas broiler, and a fan is provided for supplying a positive air flow through the ducting to the venturi tube. A still further object of this invention is to provide such a positive air flow apparatus in which the fan draws the air from over the top of the exterior of the oven for reducing the temperature above the oven. Still another object of this invention is to provide such a positive air flow apparatus in which the ducting includes openings near the venturi tube for allowing air to enter the venturi tube other than the air supplied by the fan.